What is ovulation?

Ovulation refers to the release of an egg by your ovaries. Each month, part of the ovary called the ovarian follicle releases an egg once it is mature. After it is released, the egg will then travel down one of your fallopian tubes. The lining of the uterus thickens in case the egg is fertilized. The egg only survives for about 12 to 24 hours and if isn’t fertilized, the egg disintegrates and the uterine lining will shed (i.e. you get your period).

The egg is also known as an ovum, oocyte, or female gamete. Typically only one egg is released during ovulation but more than one can occur, and if fertilized results in a multiple pregnancy. There is no set pattern or order as to which ovary ovulates each month, it can be the same one or they can alternate. A woman is born with all the eggs she will ever have and as she ages the quality and quantity diminish.

Understanding how ovulation happens and when it takes place can help achieve or prevent pregnancy, as a woman is more fertile during this time.

How and when does ovulation occur?

Ovulation and hormonal release during the menstrual cycle are controlled by a part of the brain called the hypothalamus. It sends signals for the body to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH). FSH stimulates the growth and maturity of eggs in the ovaries and LH plays in important part in triggering the release of an egg from the ovary.

The follicular phase is the first part of the ovulation cycle. This phase starts the first day of the last menstrual period and continues to ovulation. The length of this phase can last anywhere from 7 days to 30 days. During this phase the ovarian follicles are stimulated until one large mature follicle emerges that will then rupture to release an egg during ovulation. In a typical 28 day cycle, this usually occurs around day 14 however many healthy fertile women will have a cycle longer or shorter than this.

The luteal phase is the second half of the cycle. The luteal phase is typically 12-16 days from the day of ovulation. This means that the day of ovulation will determine how long a woman’s cycle is and when the next menstruation will begin.

Ovulation Symptoms

Not everyone experiences symptoms with ovulation however some recognised symptoms are:

• Ovary discomfort or pain on one side, also called mittelschmerz
• An increase in vaginal discharge which is often clear and stretchy.
• Breast tenderness
• Light bleeding or spotting
• Increased sexual drive

When are the most fertile days?

Most women are most fertile in the five days before ovulation and on ovulation day itself. An egg lives for about 12-24 hours after you ovulate, and sperm can live for up to five days. Having regular sex in the lead up to ovulation means that once ovulation occurs, there should theoretically be enough sperm on “standby” to fertilise the egg within 24 hours after its release.

Tracking Ovulation

There are different ways that you track ovulation at home:

• During ovulation, the cervical mucus increases in volume and becomes thicker due to increased estrogen levels - sometimes it is likened to being like egg white. Checking your cervical mucus can provide an indication for ovulation.
• Basal Body Temperature (BBT): There may be a slight increase in BBT after ovulation has occurred. This is driven by the hormone progesterone, which is secreted when an egg is released. Tracking your temperature can help you to identify when ovulation has occurred. Women are generally most fertile for 2 to 3 days before the temperature reaches its maximum.
• Ovulation predictor kits (OPK): available from pharmacies they detect the increase of LH in your urine just before ovulation. Ovulation may occur within a day or two of the test line being as dark or darker than the control line.
• Fertility monitors: are a more expensive option. They track estrogen and LH to help identify the six days of your fertile window.

What if you aren’t regularly ovulating? 

After a few months’ of tracking you may notice that you’re not ovulating regularly or at al. Factors such as stress, diet, polycystic ovary syndrome (PCOS) may affect the regularity of ovulation.

Consider talking to your healthcare provider who can help to identify any conditions that may be causing irregular ovulation.